Polyethylene-based resin foam sheets have been used as basic materials of cushioning materials, wrapping materials and others because they have moderate flexibility and cushioning property and are therefore unlikely to damage the articles wrapped therewith. In particular, a polyethylene-based resin foam sheet containing an antistatic agent and having a surface resistivity of approximately 1×109 to 1×1013Ω has been used as a wrapping material for electric components or glass substrates that dislike dust or static electricity.
Conventionally, a surfactant, such as a glycerin fatty acid ester, has been used as an antistatic agent to be blended in polyolefin-based resins and so on. However, such a surfactant can bleed out from the foam sheet onto the article wrapped therewith and contaminate the article. Patent Document 1 discloses a foam sheet using a polymeric antistatic agent, instead of a surfactant, as an antistatic agent to reduce contamination of the surface of an item with which it contacts, such as the article wrapped therewith. Patent Document 2 discloses a polyolefin-based resin foam sheet including a foam layer, and a layer provided on at least one side of the foam layer and containing a polymeric antistatic agent as an antistatic agent. The polyolefin-based resin foam sheet can provide an antistatic effect without being significantly affected by the humidity conditions in the air and has flexibility and cushioning property.